Advanced System Troubleshooting - Komatsu 830E Shop Manual

ADVANCED SYSTEM TROUBLESHOOTING

NO ALTERNATOR OUTPUT
STATIC TEST - ENGINE OFF, KEY ON, BATTERY
SWITCH ON.
Identify and locate "B+", "E", and "R" and ground ("B-
") terminals on alternator and check for link from ter-
minal "R" to "E". (See Figure 2-4.)
GO TO ALTERNATOR"
Test for battery B+ voltage (__________V) at "B+"
terminal on alternator:
If there is no B+ voltage on "B+" terminal,
repair VEHICLE
Continue test.
If B+ voltage is present on "B+" terminal,
continue test.
Remove strap between "R" and "E" terminal.
Connect a 12 gauge jumper wire from the
"B+" terminal on alternator to the "E" terminal
on alternator.
DAMAGE WILL OCCUR IF UNIT IS OPERATED
WITH STRAP CONNECTED AND B+ APPLIED!
Hold a steel wrench or screwdriver near
alternator drive pulley: wrench or screwdriver
held near drive pulley will be attracted to
pulley by magnetism.
• If there is no magnetic attraction, alternator may
not be turned on. Go to "Regulator Test" that
follows and continue test.
• If there is magnetic attraction, alternator is good
and regulator should be considered good.
Alternator will produce
regulator is on. This test only shows regulator as
either on or off.
NOTE: Alternator may not be turned on when engine
is operating. Go to "R" terminal test next, to prove if
vehicle "E" circuit will turn alternator on.
D2-8
24V/240A Self Energized
wiring as necessary.
electricity because
24 VDC Electric Supply System
GO TO "R" TERMINAL ON ALTERNATOR
With engine running, measure value of AC
voltage from "R" terminal to "Ground".
• If no AC volts are present, alternator is not
capable of turning on regulator.
NOTE: On a new, first time start up of an alternator,
the alternator may test at less than 5 volts on "R"
terminal. The cause of this problem may be loss of
residual magnetism within the alternator during
shipping and handling of the alternator. To restore
the residual magnetism: With engine off and battery
switch on, momentarily (1-2 seconds) connect a
jumper wire from "B+" terminal to "E" terminal. (May
spark - this is OK.) Remove jumper and restart
engine. Alternator should generate properly once the
residual magnetism is restored.
• If AC voltage is approximately 14 Volts, alternator
is properly turned on and output of alternator will
be approximately 28 Volts.
• If AC voltage is 3 Volts to 5 Volts, alternator is
NOT turned on (regulator is OFF) but alternator is
capable of turning on a GOOD regulator. NOTE:
This test shows only if alternator is capable of
energizing regulator. To check harness from
alternator to regulator go to "Regulator Connector
On Alternator" test. Continue testing.
Vehicle Charging Circuit Test Is Now Complete:
Remove all jumper wires from alternator used to test
charging circuit.
RE-TEST CHARGING CIRCUIT FOR OPERATION
with ENGINE RUNNING.
Check charging system voltage with engine running.
If no charge voltage, test for voltage at "E"
terminal of alternator, with engine running.
If no voltage on "E" terminal, shut engine
down and inspect link from "R" terminal to
"E".
Run engine and re-test charging circuit.
D02023